Extraction of tire characteristics combining direct TPMS and tire resonance analysis

Abstract

Embodiments relate to tire characterization systems and methods for combining direct tire pressure monitoring systems (TPMS) and tire resonance analysis in indirect tire pressure monitoring systems (TPMS) for the extraction of tire characteristics to characterize other tire parameters. In embodiments, iTPMS and methods that utilize anti-lock braking system (ABS) sensed signals coupled to an electronic control unit (ECU) that may comprise circuitry and/or controllers to process the sensed signals using a resonance frequency analysis (RFA) technique can be combined with direct tire pressure sensor measurements from direct TPMS systems. Because direct TPMS systems deliver a precise value of a tire characteristic (for example, tire pressure), one of the unknown parameters that influence the resonance effects can be removed. As a results, the detected resonance can be used to characterize another tire parameter that would not be accessible without knowledge of the precise value of the tire characteristic delivered by the direct TPMS system.

What is claimed is: 
     
       1. A tire characterization system, comprising:
 a sensor configured to provide a wheel speed signal; 
 a direct tire pressure monitoring system (TPMS) including at least one sensor configured to provide a direct measurement of a characteristic of the tire; and 
 a processing unit configured to process the wheel speed signal to identify at least one tire vibration mode and use the identified at least one tire vibration mode and the direct measurement to estimate a characterized parameter of the tire. 
 
     
     
       2. The tire characterization system of  claim 1 , wherein the sensor configured to provide a wheel speed signal is a component of an indirect tire pressure monitoring system (TPMS). 
     
     
       3. The tire characterization system of  claim 1 , wherein the processing unit is configured to process the wheel speed signal by using a resonance frequency analysis (RFA) that includes a spectral analysis for identifying the at least one tire vibration mode in the wheel speed signal that depends on at least two unknown parameters of the tire, and
 wherein the processing unit is configured to process the direct measurement by removing at least one of the unknown parameters in order to estimate the characterized parameter, the characterized parameter being a non-measured unknown parameter that influences the resonance. 
 
     
     
       4. The system of  claim 2 , wherein the indirect tire pressure monitoring system (TPMS) further comprises:
 an antilock braking system (ABS) configured to provide the wheel speed signal; and 
 an electronic control unit (ECU) coupled to the ABS and configured to process the sensed wheel speed signal, 
 wherein at least one of the processing unit or the indirect TPMS is a component of the ECU. 
 
     
     
       5. The system of  claim 3 , wherein the sensor is a pressure sensor. 
     
     
       6. The system of  claim 5 , wherein one of the at least two unknown parameters of the tire is tire pressure and the characterized parameter is tire material temperature. 
     
     
       7. The system of  claim 3 , wherein the processing unit is further configured to isolate a second of the at least two unknown parameters that influences the resonance and process the direct measurement to remove the second unknown parameter as an unknown parameter in the estimation of the characterized parameter of the tire. 
     
     
       8. The system of  claim 7 , wherein two of the at least two unknown parameters are tire pressure and tire material temperature, and the characterized parameter is one of state of material age or tire profile thickness. 
     
     
       9. The system of  claim 3 , wherein the processing unit is further configured to compare the removed at least one unknown parameter to the corresponding direct measurement in order to determine a reasonability of the direct measurement prior to estimation of the characterized parameter. 
     
     
       10. A method of characterizing at least one parameter of a vehicle tire, the method comprising:
 obtaining at a processing unit data representative of a wheel speed of the tire from a sensor; 
 analyzing the data using the processing unit; 
 obtaining at the processing unit a direct measurement from at least one sensor corresponding to an unknown parameter; 
 incorporating the direct measurement into the analyzed data to remove the unknown parameter using the processing unit; and 
 characterizing a parameter of the vehicle tire using the analyzed data that incorporated the direct measurement using the processing unit. 
 
     
     
       11. The method of  claim 10 , wherein analyzing the data comprises using a signal processing system to determine at least one resonance parameter associated with the data,
 wherein the method further comprises analyzing the at least one resonance parameter using the signal processing system to isolate the unknown parameter, and 
 wherein incorporating the direct measurement into the analyzed data comprises incorporating the direct measurement into the at least one resonance parameter. 
 
     
     
       12. The method of  claim 11 , wherein the at least one sensor for obtaining the direct measurement is a pressure sensor, and wherein the unknown parameter is tire pressure and the characterized parameter is tire material temperature. 
     
     
       13. The method of  claim 11 , wherein obtaining data representative of wheel speed of the tire comprises extracting data from an antilock braking system (ABS) for a tire. 
     
     
       14. The method of  claim 11 , further comprising:
 analyzing the at least one resonance parameter to isolate a second unknown parameter; 
 obtaining a second direct measurement from a second at least one sensor corresponding to the second unknown parameter; and 
 incorporating the second direct measurement into the at least one resonance parameter to remove the second unknown parameter. 
 
     
     
       15. The method of  claim 14 , wherein the unknown parameter is tire pressure, the second unknown parameter is tire material temperature, and the characterized parameter is a state of material age or a tire profile thickness. 
     
     
       16. The method of  claim 11 , wherein the at least one resonance parameter comprises one of a resonance frequency, a resonance peak height, and a Q-factor of the resonance. 
     
     
       17. The method of  claim 11 , further comprising comparing the unknown parameter to the direct measurement using the processing unit in order to determine a reasonability of the direct measurement. 
     
     
       18. A tire characterization system comprising:
 at least one sensor configured to provide at least a direct measurement of a characteristic of the tire; 
 a wheel speed sensor configured to provide a wheel speed signal; and 
 an electronic control unit (ECU) coupled to the wheel speed sensor and configured to:
 process the wheel speed signal, to identify at least one tire vibration mode associated with the processed wheel speed signal, and 
 process the direct measurement and the identified at least one tire vibration mode in order to estimate a characterized parameter of the tire. 
 
 
     
     
       19. The tire characterization system of  claim 18 , wherein the ECU is configured to process the sensed wheel speed signal using a resonance frequency analysis (RFA) that includes a spectral analysis identifying the at least one tire vibration mode in the wheel speed signal,
 wherein the ECU is further configured to isolate at least one unknown parameter that influences a resonance, and 
 wherein the ECU is further configured to process the direct measurement by removing the at least one unknown parameter that influences the resonance in order to estimate the characterized parameter. 
 
     
     
       20. The tire characterization system of  claim 19 , wherein the at least one sensor is a pressure sensor, and wherein the unknown parameter is tire pressure and the characterized parameter is tire material temperature.